Nanoparticles are often used in nanoengineering for diverse applications, such as being used as an attachment point for other molecules or to interact with electromagnetic radiation. A nanoparticle is generally defined as a particle between 0.1 and 100 nanometers (nm) in size.
FIGS. 1A to 1D illustrate some example uses for nanoparticles. As shown in FIG. 1A, nanoparticle 10 can serve as a carrier particle to transport deoxyribonucleic acid (DNA) molecule 12 or as an anchor point for DNA molecule 12. FIG. 1B illustrates an example where nanoparticle 10 is used for its intrinsic mechanical or chemical properties to interact with electromagnetic radiation 14. In some applications, nanoparticles 10 may be deployed in solution 18 as shown in FIG. 1C, or on solid substrate 20 as in FIG. 1D.
Nanoparticles can be composed of various materials, depending on the application. Commonly used nanoparticle materials include metals and semiconductor particles, such as quantum dots. Such particles typically have somewhat spherical or crystalline shapes.
The use of nanoparticles smaller than about 20 nm in devices, such as sensors for DNA sequencing, is often limited by current methods of fabricating nanoparticles. Even state of the art device fabrication techniques such as extreme Ultra-Violet (UV) lithography, or photolithography with phase shifting masks, and multiple patterning, will only produce nanoparticles of about 20 nm. In addition, nanoparticles smaller than 20 nm that are formed by methods such as by precipitating crystals in a solution may have a variety of different shapes. These nanoparticles may not be compatible with being placed on a surface or substrate in forming a device. The nanoparticle may then undesirably move if it is not energetically stable when placed on the surface or substrate. In addition to the need for smaller nanoparticles, there is also a need for being able to consistently fabricate nanoparticles of a defined shape that can be precisely and stably positioned on a surface or a substrate.